1. Field of the Invention
The present invention relates to composite electronic components and methods for manufacturing the composite electronic components. More particularly, the present invention relates to a composite electronic component in which a plurality of types of substrates having different characteristics are integrated to provide a desired function and to achieve miniaturization and profile reduction, and to a method of manufacturing the composite electronic component.
2. Description of the Related Art
In recent years, with miniaturization and enhancement of functions of mobile communication devices, such as portable phones and electronic devices, miniaturization and enhancement of functions of electronic components have rapidly progressed. For example, in Japanese Patent No. 3375555 (Patent Document 1), a circuit component built-in module having a circuit components built therein and being modularized and a method of manufacturing the circuit component built-in module are disclosed.
The circuit component built-in module described in Patent Document 1 includes an electrical insulating substrate made of a mixture including an inorganic filler and a thermosetting resin, a plurality of wiring patterns disposed on at least one major surface of the electrical insulating substrate, and a circuit component embedded in the electrical insulating substrate and electrically connected to the wiring patterns. The circuit component and the wiring patterns are electrically connected through conductive adhesive or bumps. In addition, in Patent Document 1, a circuit component built-in module having a multilayer structure in which a plurality of electrical insulating substrates are laminated is disclosed. In Patent Document 1, an inner via connection method is used to increase the density and enhance the functions of the circuit component. In addition, a mixture including an inorganic filler and a thermosetting resin is used as a material for making the electrical insulating substrate, in order to increase reliability.
However, in a conventional composite electronic component, as in the circuit component built-in module described in Patent Document 1, a plurality of wiring patterns are disposed on at least one major surface of an electrical insulating substrate, and a circuit component connected to these wiring patterns is embedded in the electrical insulating substrate. Thus, when a plurality of different types of circuit components are built into the electrical insulating substrate so that the electrical insulating substrate has various functions, the heights of the circuit components are limited to the height of the electrical insulating substrate. In addition, since it is difficult to arrange a wiring layer inside the electrical insulating substrate in which the circuit components are embedded, despite the presence of high-density wiring, it is inevitable that the wiring layer has to be provided on the top or bottom surface of the electrical insulating substrate. Thus, there has been a problem in that it is difficult to reduce the profile of a composite electronic component.